Steps

• Open any project in Qt Creator
  Add a "Make" deployment step.

• Leave the field Override C:\Qt\Tools\QtCreator\bin\jom.exe empty.
  Optionally add make arguments in the second field, e.g "target".

• Deploy the project.

• The project fails to deploy with:
  Could not start process "" target

Quick fix

• Set C:\Qt\Tools\QtCreator\bin\jom.exe in the Override C:\Qt\Tools\QtCreator\bin\jom.exe field

Note

Same issue with mingw32-make when using a MinGW kit.